Manual editing and update

[www.kite-store.net]

Hello,
I'm running a PS based store and i'm planning to update it to 1.4
I'm not familiar with programming languages so the answer must be easy to understand (please).
My question is:
Is there any file or files where product information such as price, descriptions, meta information is stored so i can edit it offline?

I have some combinations of products (size, colors), but when added to cart it adds all features. What have i done wrong?

you can test it at www.kite-store.net by selecting an wetsuit. It will add to cart all sizes, not only the one selected.
Thanks
AG